1. Field of the Invention
The present invention relates generally to an internal combustion engine and more specifically to an induction sensor arrangement for a fuel injected engine or the like which enables an accurate determination of the amount of air inducted thereinto and which obviates the sharp overly rich/lean deviations in the air-fuel ratio which tend to be produced during transitory modes of engine operation.
2. Description of the Prior Art
In order to optimally control fuel injected engines it is vital to accurately sense the amount of air being inducted into the engine. To achieve this it is well known to directly sense the amount of air being inducted using hotwire/vortex and flap type air flow sensors.
However, these sensors tend to be overly responsive to the to the pressure pulsations which occur in the induction system. Accordingly, the accuracy thereof is apt to vary widely depending on the mode of the operation of the engine. This induces the drawback that as the amount of fuel supplied to the engine is determined using the sensed induction volume rich/lean spikes in the air-fuel control characteristics occur. This causes the torque generated by the engine tends to undesirably fluctuate with the accuracy of the induction system. Moreover, the above mentioned devices are both bulky and expensive and thus add to the cost of the vehicle as well as consuming a relatively large amount of the limited space available in the engine compartment.
As an alternative to the above mentioned direct sensing technique it is also known to indirectly sense or derive the amount of air being inducted by sensing a number of engine operation parameters which vary with the amount of air being inducted and using the data to predict the same on the basis of pre-recorded data. For example, it is known to sense the engine speed, induction pressure and throttle position and utilize this data to obtain an induction air amount by way of a table look-up technique. However, this method encounters the problem that the compilation of the data tables (which are recorded in the form of a four parameter system and which can be depicted in the form of a three dimensional contour map) requires large amounts of expensive memory space. Moreover, these systems have not proven sufficiently effective during transitory modes of engine and vehicle operation.